EP0396696B1 - Process for repairing an inaccessible domestic pipe using a remote-controlled device operating in the main - Google Patents

Abstract

A device for repairing a main (1) can also be used to repair a leaking, corroded section of a branch pipe (2) which opens into the main. The device has a toothed rod (17) which can be extended approximately radially and rotated in the axis of the branch pipe by rotation of a pipe end cover plate (14). A hose (23), which extends from the centre of the pipe end cover plate (14), is fastened to the free end of the toothed rod by means of a pipe piece (29). An air bubble (31) is placed on the pipe piece (29) and inflated by compressed air blown through the hose until it becomes lodged in the branch pipe itself. After the air bubble is detached, a cover plate is mounted on the end of the hose and a hardenable material is pumped through the hose into the cavity formed between the cover plate and the air bubble (31). If the branch pipe is to be brought into service again, the hardened material is drilled out of the branch pipe up to the diameter of the branch pipe (2) by the same or another device also operating in the main pipe (1).

Description

The invention relates to a method for repairing a non-accessible, wastewater-carrying house supply line in the section with which it opens into a likewise non-accessible main line, by means of a remote-controlled device operating in this main line.

Pipes that discharge wastewater from buildings and that are referred to as house supply lines usually flow into the main pipe under a street that leads past the buildings. Both they and the main line are almost always of a diameter that makes them impossible to walk on. A repair is only possible by means of remote-controlled devices, which are already known from numerous documents, without the line network having to be dug out and the road narrowed for a long time or even being completely closed to traffic. The devices mentioned can only be used for repairs in the main line.

The damage that occurs to house supply lines consists of leaks, actual holes or even in one through Corrosion caused this line to completely disappear in the relevant section, leaving only the soil surrounding the original house supply line. However, there is a risk that wastewater can penetrate this and thus the groundwater. The section mentioned is usually located where the house supply line in question opens into the main line. The repair can therefore be carried out from the main line. This also applies if the house supply line is no longer used. This is usually the case when the original building is replaced by a new one, in which the house supply lines hardly ever come to the same place. The old house supply lines must therefore not only be closed, but also repaired in the section mentioned, because otherwise there may also seep in the ground if there is a jam in the main line. Since the main line is never completely excavated in a new building, a repair or Decommissioning required by her.

Processes in which one works from the main line, however, have so far only been known for repairing it itself. An insert tube is always used, which is inserted into the main line, as shown for example in EP-A-0 253 588, WO 86/05569 or GB-A-2 147 682. The main line is thus simply repaired. However, the disadvantages are a reduced flow capacity and the need to locate the house supply lines that are now isolated from the main line if they are to continue to be in operation and to drill the insert pipe there. Once these complex measures have been carried out, the sometimes considerable space between the main line and the insert pipe must be filled with a hardening compound, and this must now be filled in from the main line. So that the house supply line is not closed again, an air bubble is pushed into it in such a way that either its rear end still remains in the drilled hole in the insert tube or it is there on one attached cover plate is attached, whereupon it is inflated. Then another hole has to be drilled on the insert tube so that the mass can be filled through it. The defective spot on the house supply line is not repaired by this. The filled mass flows practically without pressure in the longitudinal direction of the gap and is therefore not able to overcome the pressure of the air bubble, which has expanded to the surrounding earth at the repair site and thus takes up the space that the mass should fill.

The methods mentioned are therefore not only unsuitable for the intended purpose, but also unsuitable, because main lines can also be repaired without an insert pipe, e.g. CH-A-640 623 or EP-B-0 025 204 show. Not only can this avoid the capacity-reducing diameter reduction of the main line, but also the repair device used there, matched to its original diameter, which would not fit into the insert pipe. It is not known, as the state of the art shows, to also use it to repair the branch line, i.e. house supply line, at its junction.

It is therefore assumed that the method known from EP-A-0253 588 according to the preamble of claim 1, the known device mentioned therein having a compressed air supply, onto which an inflatable air bubble is placed in a first, also known method step and by swiveling and then Feed the compressed air supply through at least part of it into the house supply line and then pump it up to the point of contact. In a later, also known process step, a cover plate and a hardening compound are brought through the main line to the mouth of the house supply line to be repaired. The inventive method now differs from this entire prior art by the characterizing features of claim 1.

As can be seen, this process also ensures the pressure build-up and thus the necessary compression of the mass at the repair site. It is so simple that the known device only has to be slightly modified for its implementation, which is also of great advantage.

Fig. 1

eine Aufsicht auf die dafür verwendete Vorrichtung,

Fig. 2

den Beginn des Verfahrens,

Fig. 3

eine erste, daran anschliessende Phase,

Fig. 4

das Ausfüllen des Hohlraumes an der Schadstelle,

Fig. 5

eine weitere, fakultative Phase, nämlich das Ausbohren der im Hohlraum ausgehärteten Masse,

The method according to the invention is to be explained in more detail, for example, using the present drawings, in which:

Fig. 1

a supervision of the device used for this,

Fig. 2

the beginning of the process,

Fig. 3

a first, subsequent phase

Fig. 4

filling the cavity at the damaged area,

Fig. 5

a further, optional phase, namely the drilling out of the hardened mass in the cavity,

Fig. 1 shows only schematically the device in supervision. This corresponds to that according to EP-PS 0 211 825, which is why only the components necessary for understanding the method described below are shown; Details can be found in the cited publication. The device, and this is one of the essential advantages of the invention, only needs to be modified slightly so that, in addition to the repair of the main line 1 for which it was developed, it can also carry out the repair of the house supply line 2 flowing into it. Both lines 1, 2 are of a diameter that makes any inspection impossible. It is therefore only possible to use a remote-controlled device which is introduced into the main line 1 at some point through a shaft which is large enough for an inspection.

The device is a motor-driven car, which in the present case runs on tracks 3; but it could also be normal bikes. The caterpillars 3 or wheels carry a base plate 4 on which a vertical end wall 5, a bearing plate 6 and a wide support bearing 7 are attached. The support bearing 7 serves to support a hollow cylinder 8 which has a recess over part of its length such that it only forms a half-shell there. This hollow cylinder 8 is rotatably mounted about its longitudinal axis in the support bearing 7 and serves to receive a tube 9 which is inserted into the hollow cylinder 8 from the right end in the figure and is releasably connected to it by interlocks, not shown. The hollow cylinder 8 is connected through the bearing plate 6 to a gear 10 which is driven by two motors 11 arranged parallel to one another. With running engines, therefore, not only the hollow cylinder 8 rotates, but also the tube 9 and a flange 12 at the insertion end of the hollow cylinder. A device 13 is placed on the right end of the tube 9 in FIG. 1, which was previously used for applying filler compound in the main line 1 and for spreading this compound on the inner wall thereof, but now for the new purpose is slightly changed. As in the past, it essentially has a tube cover 14 which can be easily attached to the tube 9 by means of easily detachable closures 15, which are only shown symbolically. This pipe end cover 14 carries two fixed guides 16 for two displaceable racks 17, which can be seen above all from FIGS. 2-4. These approximately radially displaceable toothed racks 17 each have a parallelogram joint 18 at their ends, on the free end of which a tool could be mounted. These joints 18 actually serve to guide the tools over out-of-round points in the main line, that is, to compensate for these out-of-roundness. They are not required for the present purpose. The racks 17 are shifted by electric motors 19, which are mounted on the flange 12 and move the racks via shafts 20, a claw coupling 21 and a pinion 22 (FIG. 2). The claw couplings 22 are necessary so that the entire device 13 can be easily removed from the pipe 9 and subsequently placed on it again, because this pipe also contains the filler and must be filled again after it has been used up. to be replaced by a filled one. This mass is normally brought through a flexible hose 23 from the center of the pipe end cover 14 to the spatula at one end of the one rack. For this purpose, compressed air is used, which is brought in from the left end of the wagon via a line 24 and is introduced into the pipe 9 via a connection block 25, a control valve 26 and a rotating sleeve 27. The rotating sleeve 27 is necessary because the control valve 26 is fixedly mounted, but the hollow cylinder 8 and the tube 9 are rotatable about their longitudinal axis. The device 13 also rotates with these.

The above description of the device now makes it possible to better explain the method according to the invention with reference to FIGS. 2-5. The car is placed within the main line 1 in the place of the house supply line 2 to be repaired, which thanks to the television camera mounted on it below the tube 9 on the flange 12 28 (FIG. 1) is readily possible; this moves when the flange 12 rotates on a circular path around the longitudinal axis of the pipe 9, so that the junction of the house supply line 2 can be made visible and can be studied in detail. The hose 23 is now pushed at its free end over a pipe section 29 and fastened with a hose clamp 30. The inlet opening of an air bubble 31 is pushed onto this pipe section 29, which is mounted at the end of the relevant parallelogram joint 18. This air bubble is initially folded up so that it does not hinder the movement of the car, and is held together with a thin rubber ring 32 known from office and household. By switching on the motors 11, the entire device 13 is now rotated to such an extent that the one rack 17 can then be advanced by means of the motor 19 assigned to it and the pinion 22 exactly in the longitudinal axis of the house supply line 2. If the air bubble has reached the correct position according to FIG. 3, it is inflated by the compressed air system of the car, that is to say by the line 24 and via the pipe section 29. The rubber ring 32, which is not set up for such an expansion, is torn here. The air bubble 31 is pumped up until it bears against the inner wall of the line 2. Here it is anchored to this relatively rough inner wall in such a way that when the toothed rack 17 is subsequently moved back, it is torn off from the tube piece 29 and remains in the assumed position. A check valve in the air bubble 31 prevents the air from escaping from the separated air bubble.

Fig. 4 shows how to proceed. The rack 17 is moved back and the entire carriage in the main line 1 is moved back to the service shaft. A cover plate 33 is now placed there on the end of the parallelogram joint 18. This has a narrow passage pipe 34 so that the hose 23 can now be attached to it. During this assembly, the pipe 9 was also filled with filler. The car now drives back to the house supply line 2, and the cover plate 33 is placed over the mouth of the same. When the compressed air supply is switched on Now the filler (epoxy resin or a cementitious material) is pressed through the hose 23 and the passage pipe 34 and enters the cavity formed by the air bubble 31, the cover plate 33 and the earth around the corroded section, which it fills. After curing, a solid closure 35 was created, but thanks to the air bubble 31, it required only relatively little material. Without the air bubble 31, much more material would have had to be brought in, which would also have been considerably less compressed due to the lack of a base and would therefore also have been less solid.

If the intention was to shut down the house supply line 2, the work is finished. Even before it has completely hardened, you can use the other rack, which is not used here, to move a spatula that was already present in the original device over the filler and smooth it out. First of all the cover plate 33 must of course be removed. The movement of the spatula is described in EP-PS 0 211 825. The air bubble 31 remains enclosed.

However, if the line 2 is to remain in operation, the closure 35 must be drilled out, as can be seen in FIG. 5. The device described above is now replaced by one which has a radially advanced drill or milling head 36. Such tools are known; one of them is described in EP-PS 0 025 204, another in WO / 7154. If the device for drilling and filling is set up as in the first-mentioned publication, only the cover plate 33 has to be removed. The closure 35 is thus drilled out from the main line 1 to the diameter of the house supply line 2. The air bubble 31 is destroyed when the closure 35 is pierced; their remains are later washed away by the water flowing again in line 2 into main line 1 and from there.

It is important with this method that both in FIG. 4 and especially in FIG. 5 the soil, which is usually strong and often total corrosion of the relevant section of line 2 was exposed unprotected, is now sealed again, and that in this way entry of waste water into the groundwater is prevented. As already mentioned, the wastewater can often also penetrate from the main line 1 if the main line is used up to its capacity.

The method described also has the advantage that the already repaired and newly drilled house supply line (Fig. 5) can be shut down at any time afterwards by re-applying a closure according to Fig. 4, but then no longer drilling it. Any mix-ups in the house supply lines, which can occasionally occur, can also be easily corrected.

Claims (2)

1. Process for repairing an inaccessible domestic pipe conducting sewage water, in that section in which it joins an also inaccessible main (1), by means of a remote-controlled device operating in that main which is equipped with a conduit for pressurized air (16, 17, 23) rotatable about its longitudinal axis and radially extendable to it, a first process step comprising said conduit to be provided with an inflatable air bag to be placed on it, to be introduced into the domestic pipe over at least a part of its length by rotating and subsequently advancing the pressurized air conduit and to be inflated until contacting said pipe; a subsequent second step comprising the withdrawal of the pressurized air conduit which thereby separates from the air bag, the air bag remaining inflated also after this separation; a further process step comprising a curing material (35) brought to the mouth of the domestic pipe (2) through the main (1), characterized in that the section to be repaired is delimited at one of its ends by placing a cover (33) onto the interior wall of the main at said mouth, that the introduction of the air bag into the main, referred to in the first process step, is carried out to such an extent that the air bag contacts, over at least said part of its length, the ultimate still intact section of the domestic pipe in order to delimit the adjacent section to be repaired also on this connection of the two sections, opposed to its said first end, and in this manner forming a space separated from the interior of the main as well as from the interior of the domestic pipe and definitely delimited only by the cover (33), the end of the air bag which protrudes from the intact section of the domestic pipe and by the soil surrounding the section to be repaired and that finally this space is filled with the curing material through at least one passage leading through the cover.
2. Process according to Claim 1, during which the domestic pipe repaired in this manner is put back in operation, characterized in that, after curing of said material, the cover (33) is removed and that, by means of a boring or grinding head (36) brought to site within the main (1) by remote control and radially extended there, the material is bored to the inner diameter of the still intact section of the domestic pipe.

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